Remote Measurement of a VHF Love Wave Sensor for Liquid Detection

In this paper, the remote liquid detection through the wireless interrogation of a VHF Love wave acoustic sensor is presented. In the prototype, the Love wave sensor is interrogated with a Vector Network Analyzer in a bistatic antenna configuration. The addition of salt water onto the sensor induces a repeatable change in its impedance and a change in its Radar Cross-Section (RCS) around of 0.13 dBsm. A variation in the frequency of 221 kHz and in the magnitude of the transmission coefficient 0.17 dB were measured at the resonant frequency region of the device.